executor: fix nil pointer for query on tikv_region_status with non-exist table id (#57534)

close #57530

Author: tiancaiamao

pkg/executor/infoschema_reader.go

@@ -1962,7 +1962,7 @@ func (e *memtableRetriever) setDataForTiKVRegionStatus(ctx context.Context, sctx
 			for _, tableID := range extractorTableIDs {
 				regionsInfo, err := e.getRegionsInfoForTable(ctx, tikvHelper, is, tableID)
 				if err != nil {
-					if errors.ErrorEqual(err, infoschema.ErrTableExists) {
+					if errors.ErrorEqual(err, infoschema.ErrTableNotExists) {
 						continue
 					}
 					return err
@@ -1982,6 +1982,10 @@ func (e *memtableRetriever) setDataForTiKVRegionStatus(ctx context.Context, sctx
 			return err
 		}
 	}
+	if allRegionsInfo == nil {
+		return nil
+	}
+
 	tableInfos := tikvHelper.GetRegionsTableInfo(allRegionsInfo, is, nil)
 	for i := range allRegionsInfo.Regions {
 		regionTableList := tableInfos[allRegionsInfo.Regions[i].ID]
@@ -2006,7 +2010,7 @@ func (e *memtableRetriever) setDataForTiKVRegionStatus(ctx context.Context, sctx
 func (e *memtableRetriever) getRegionsInfoForTable(ctx context.Context, h *helper.Helper, is infoschema.InfoSchema, tableID int64) (*pd.RegionsInfo, error) {
 	tbl, _ := is.TableByID(ctx, tableID)
 	if tbl == nil {
-		return nil, infoschema.ErrTableExists.GenWithStackByArgs(tableID)
+		return nil, infoschema.ErrTableNotExists.GenWithStackByArgs(tableID)
 	}
 
 	pt := tbl.Meta().GetPartitionInfo()

tests/realtikvtest/sessiontest/session_fail_test.go

@@ -325,3 +325,10 @@ func TestTiKVClientReadTimeout(t *testing.T) {
 	explain = fmt.Sprintf("%v", rows[0])
 	require.Regexp(t, ".*TableReader.* root  time:.*, loops:.* cop_task: {num: 1, .*num_rpc:(3|4|5).*", explain)
 }
+
+func TestIssue57530(t *testing.T) {
+	store := realtikvtest.CreateMockStoreAndSetup(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use information_schema")
+	tk.MustQuery("select * from  TIKV_REGION_STATUS where table_id = 81920").Check(testkit.Rows())
+}